"Wireless ad hoc networks can be used to solve challenging end-to-end requirements such as rescue operations, where there is a temporary destruction of infrastructure due to natural calamities or there is no availability of infrastructure at all. In wireless ad hoc networks, hosts which communicate to each other form a random network topology using a variety of communication media. There are many challenges in this complex distributed system; the primary one being the need to provide fault tolerance in connection failure environment to route information from one node to another.
This presentation focuses on fault-tolerance in routing information for rescue operations. In general, if nodes fail, the connection is rerouted from the source and QoS will have to be re-established. This global fault-tolerance method means that the source will have to be recomputed and a new QoS path has to be renegotiated which, depending on the network size, could be costly in terms of computation and communication time necessary for path negotiation (negotiation includes implementation of the new path). If multiple sources were using the failed node in their QoS path, each affected source must re-compute and renegotiate a new path, which is an expensive proposition.
”Repair method” in clustered protocol is the solution that is an efficient fault-tolerance technique which eliminates costly method of re-compute and renegotiation in routing information from source to destination. Each node functions not only as source or destination but also as a router. To achieve this, fault-tolerant algorithm is implemented which makes it possible for the intermediate nodes to efficiently repair the failed connection locally. This has significant benefits over the standard practice of rerouting from the source for QoS traffic.